tbuckley/cabot-search huggingface dataset:
Abstract P3035: Time-of-intake Regulates Glucocorticoid Effects On Heart Metabolism And Function Through Cardiomyocyte-autonomous Mechanisms
Authors: Mattia Quattrocelli, Michelle Wintzinger, Karen Miz, Manoj Panta, Hima B Durumutla, Ashok D Prabakaran
Journal: Circulation Research (2022)

Glucocorticoids are circadian regulators of energy balance. However, the cardiomyocyte-autonomous mechanisms of glucocorticoid action on heart metabolism remain unresolved. Also, little attention is given to the impact of circadian time of intake on the effects of these drugs in heart. Here, we investigated whether circadian time of exposure gates the effects of synthetic glucocorticoids on heart metabolism and function. In single pulse experiments, we compared the effects of the glucocorticoid prednisone in wildtype (WT) hearts through light-phase- versus dark-phase-specific injections. Light-phase pulse - but not dark-phase pulse - increased NAD + and ATP levels in murine hearts in vivo for one circadian cycle post-pulse. To ask whether this effect was replicated in chronic treatment, we used the intermittent once-weekly prednisone regimen that we previously used to boost muscle metabolism without the wasting and metabolic toxicity caused by once-daily dosing. In WT mice treated for 12 weeks with once-weekly prednisone, light-phase-specific dosing gated the positive effects of treatment on NAD + , mitochondrial respiration and abundance in heart, as compared to dark-phase-specific dosing. These processes were cardiomyocyte-autonomous as the circadian-specific treatment effects were blocked by inducible cardiomyocyte-specific ablation of the glucocorticoid receptor. To probe relevance of this treatment for the injured heart, we treated mice after induction of ischemic injury. Light-phase-specific prednisone treatment significantly improved NAD + , mitochondrial function and systolic function in injured hearts. RNA-seq showed that treatment elicited a virtuous gene program of circadian metabolism in the myocardium. Indeed, the effects of treatment on heart metabolism gene cascades were dependent on the intact heart peripheral clock, as shown by mice with inducible cardiomyocyte-specific ablation of the clock factor BMAL1. In summary, our data indicate that glucocorticoids regulate cardiomyocyte metabolism in a cell-autonomous fashion hinging upon circadian-time of intake and interaction with the peripheral clock. Our work supports a role for chrono-pharmacology of ischemic heart disease with glucocorticoids.
Abstract P2018: Tmem65 Is Critical For The Structure And Function Of The Intercalated Discs In Mouse Hearts
Authors: Allen Teng, Liyang Gu, Michelle Di Paola, Robert Lakin, Zachary Williams, Aaron Au, WENLIANG CHEN, Neal I Callaghan, Farigol Hakem Zadeh, YU-QING ZHOU, Meena Fatah, Diptendu Chatterjee, Jane Jourdan, Liu Jack, Craig A Simmons, Thomas Kislinger, Christopher Yip, Peter Backx, Robert G Gourdie, Robert M Hamilton, Anthony Gramolini
Journal: Circulation Research (2022)

The intercalated disc (ICD) is unique membrane structure that is indispensable to normal heart function, yet its structural organization is not completely understood. Previously, we showed that the ICD-bound transmembrane protein 65 (Tmem65) was required for connexin 43 (Cx43) localization and function in cultured mouse neonatal cardiomyocytes. Here, we investigated the role of Tmem65 in ICD organization in vivo . A mouse model was established by injecting CD1 mouse pups (3-7 days after birth) with recombinant adeno-associated virus 9 (rAAV9) harboring Tmem65 shRNA which resulted in a 90% reduction of Tmem65 expression in mouse ventricles compared to mice injected with scrambled shRNA. Tmem65 knockdown (KD) resulted in increased mortality which was accompanied by eccentric hypertrophic cardiomyopathy within 3 weeks of injection, progressing to dilated cardiomyopathy with severe cardiac fibrosis by 7 weeks post-injection. Tmem65 KD hearts displayed depressed hemodynamics, measured echocardiographically, accompanied by electrocardiogram changes (prolonged PR intervals and QRS duration) consistent with impaired conduction, which was confirmed with optical mapping of isolated hearts. Immunoprecipitation and super-resolution microscopy demonstrated a physical interaction between Tmem65 and sodium channel β subunit (β1) in mouse hearts and this interaction appeared to be required for both the establishment of perinexal nanodomain structure and the localization of both voltage-gated sodium channel 1.5 (NaV1.5) and Cx43 to ICDs. Despite the loss of NaV1.5 at the ICDs, whole-cell patch clamp electrophysiology did not reveal reductions in Na + currents but did show reduced Ca 2+ and K + currents in Tmem65 KD cardiomyocytes in comparison to control cells. We conclude that disrupting Tmem65 function results in impaired ICD structure, abnormal cardiac electrophysiology, and ultimately cardiomyopathy.
Abstract P2107: Improving Stem Cell Models Of Duchenne Muscular Dystrophy-related Cardiomyopathy By Incorporation Of Physiologic Mechanical Stress
Authors: Dominic E Fullenkamp, Alexander B Willis, Jodi L Curtin, Ansel P Amaral, Sloane I Harris, Paul W Burridge, Alexis R Demonbreun, Elizabeth M McNally
Journal: Circulation Research (2022)

Background: Cardiomyopathy in Duchenne muscular dystrophy (DMD) is a significant driver of disease morbidity and mortality. Induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) offer the opportunity to study patient-specific mutations in the dish, however they generally suffer from immaturity. DMD is caused by mutations in the gene DMD , which codes for the protein dystrophin. Dystrophin localizes to the sarcolemma, forming part of a critical transmembrane mechanical and signaling complex that bridges the sarcomere to the extracellular matrix. Disruption of this axis leads to membrane fragility and mechanical stress is a main driver of DMD pathology. New therapies for DMD are in clinical development, including exon skipping, micro-dystrophin gene therapy, CRISPR-based gene editing, and membrane resealants, with some exon skipping strategies receiving FDA approval. The main outcomes of these therapies have been tied to improvement in skeletal muscle function with cardiac efficacy remaining understudied, despite its clear importance for patient outcomes. Results: Equibiaxial strain was employed as a physiologic mechanical stressor to simulate the in vivo mechanism of myocyte injury in an in vitro format using patient-derived DMD iPSC-CMs. By titrating strain, we determined that application of 10% strain for 2 hours robustly differentiates DMD and control iPSC-CMs using the clinically relevant biomarker LDH release as a proxy for membrane damage (control LDH release fold change: no significant change; DMD LDH release fold change: 2.51, p&lt;0.0001). We evaluated DMD biomarkers released into the media using aptamer-based proteomics profiling and identified a striking strong correlation with serum biomarkers from DMD patients. Longer duration strain (24 hours) led to cell injury in both control and DMD iPSC-CMs. A membrane resealant was evaluated in this platform, which demonstrated enhanced recovery following treatment for both DMD and control iPSC-CMs with concomitant reduction in biomarker release. Conclusions: iPSC-CM models can be improved by incorporating physiologic mechanical stress, which is a main driver pathology. This platform is especially useful for evaluating dystrophic cardiomyopathy therapeutics.
Abstract P1036: Role Of Mitochondrial Ribosomal Protein L7/l12 (mrpl12) In Diabetic Ischemic Heart Disease
Authors: Amit K Rai, Brooke Lee, Shridhar Sanghvi, Dhanendra Tomar, Dhananjie Chandrasekera, Sreejit Gopala Krishna, Devasena Ponnalagu, Mahmood Khan, Harpreet Singh, Prabhakara R Nagareddy, David A Goukassian, Rajesh Katare, Walter J Koch, Raj Kishore, Venkata Garikipati
Journal: Circulation Research (2022)

Myocardial infarction (MI) is a significant cause of death in diabetic patients. In addition, growing evidence suggests that mitochondrial dysfunction contributes to heart failure in diabetes. However, the molecular mechanisms of mitochondrial dysfunction mediating heart failure in diabetes are still poorly understood. The current study aimed to investigate the role of mitochondrial ribosomal protein L7/L12 (MRPL12) in mouse models of type II diabetes (db/db mice)and high-fat diet (HFD) mice with or without induction of MI and human hearts with or without diabetes (n=7) .Data analysis revealed an increase in MRPL12 levels in the LV tissue of HFD fed mice with MI than in LV tissues of low-fat diet-fed mice with MI, whereas MRPL12 levels remained unchanged in the db/db mice with MI. Intriguingly, we found increased MRPL12 levels in atrial appendage tissue of diabetic patients with ischemic heart disease compared to non-diabetic patients. We utilized human cardiomyocyte cell-line (AC-16) as surrogate models to delineate the mechanisms; surprisingly, adenovirus-mediated overexpression of MRPL12 with or without hyperglycemia in AC-16 cardiomyocytes does not affect mitochondrial OXPHOS . In addition, overexpression of MRPL12 had no effect on the mitochondrial ROS, mitochondrial membrane depolarization, and caspase activity in AC-16 cardiomyocytes. Whereas RNA interference (RNAi)-mediated MRPL12 silencing remarkedly reduced mitochondrial oxidative phosphorylation in AC-16 cells without any stress. In addition, knockdown of MRPL12 increased mitochondrial membrane depolarization mitochondrial ROS and reduced maximal respiratory capacity of mitochondria without any stress. Overall, our results provide new insights into the role of MRPL12 in the pathophysiology of MI in diabetes.
Abstract P1122: Coupled Myovascular Expansion Directs Cardiac Growth And Regeneration
Authors: Paige DeBenedittis, Anish Karpurapu, Albert Henry, Michael C Thomas, Tom Lumbers, Ravi - Karra
Journal: Circulation Research (2022)

Background: Heart regeneration requires multiple cell types to enable cardiomyocyte (CM) proliferation. How these cells interact to create growth niches is unclear. Here we profile proliferation kinetics of cardiac endothelial cells (CECs) and CMs in the neonatal mouse heart and find that they are spatiotemporally coupled. Methods and Results: We show that coupled myovascular expansion during cardiac growth or regeneration is dependent upon VEGF-VEGFR2 signaling, as genetic deletion of Vegfr2 from CECs or inhibition of VEGFA abrogates both CEC and CM proliferation. Repair of cryoinjury displays poor spatial coupling of CEC and CM proliferation. Boosting CEC density after cryoinjury with virus encoding Vegfa enhances regeneration. Using Mendelian randomization, we demonstrate that circulating VEGFA levels are positively linked with human myocardial mass, suggesting that Vegfa can stimulate human cardiac growth. Conclusions: Our work demonstrates the importance of coupled CEC and CM expansion and reveals a myovascular niche that may be therapeutically targeted for heart regeneration.
Abstract P1040: The Protective Effects Of Sialidase Neu3 Against Cardiac Ischemia And Reperfusion Injury
Authors: Marco Piccoli, Ivana Lavota, Simona Coviello, Andrea Ghiroldi, Federica Cirillo, Carlo Pappone, Luigi Anastasia
Journal: Circulation Research (2022)

The salvage of myocardium after acute myocardial infarction (AMI) can only be achieved by timely reperfusion. This is life-saving, however it may also lead to additional damage in the form of ischemia and reperfusion injury (IRI). Protecting cardiac tissue from IRI remains one of the greatest unmet clinical needs in cardiology. Therefore, a better understanding of IRI pathophysiology is necessary. There has been increasing recognition that the activation of specific molecular mechanisms, including the Reperfusion Injury Salvage Kinase (RISK) pathway and HIF-1&amp;#945; contributes to cardioprotection against IRI. Along this line, we previously reported that sialidase Neu3, which removes sialic acid from glycosphingolipids, controls HIF-1&amp;#945; activation via a prolyl hydroxylase-independent pathway. In fact, we found that Neu3 was up-regulated under chronic hypoxia in cyanotic congenital cardiac patients and its overexpression increased muscle cells’ resistance to hypoxic stress by activating the RISK pathway. In light of these premises, the goal of this study was to determine Neu3's involvement in the cardiac response to IRI and establish whether its inducible activation could promote cardioprotection. An IRI model in mice, obtained by temporarily blocking the LAD coronary artery, showed that Neu3 is modulated during this process. Notably, Neu3 showed progressive downregulation during the ischemic phase followed by its reactivation during reperfusion. These results were similar to the Neu3 modulation we observed in human cardiac cells (AC16) exposed to an IRI model in vitro . The overexpression of Neu3 during ischemia had beneficial effects both in terms of cell proliferation and reduction of oxidative stress after reperfusion. We found that Neu3 promotes the activation of glycolytic enzymes during the ischemic phase as well as the maintenance of the mitochondrial membrane potential, suggesting that the Neu3-overexpressing human cardiomyocyte undergoes more aerobic metabolism even in oxygen-deficient environments. In conclusion, these results support a role for Neu3 in cardioprotection against IRI, suggesting that it may be a useful therapeutic target for improving the recovery of patients who have undergone acute myocardial infarction.
Abstract P3006: A Human Arterial Cell Atlas
Authors: Paul Cheng, Albert J Pedroza, Disha Sharma, Chad S Weldy, Trieu Nguyen, Alex R Dalal, Rohan Shad, Juyong B Kim, Michael P Fischbein, Robert Wirka, Thomas Quertermous
Journal: Circulation Research (2022)

Background: Human vascular diseases are the worldwide leading causes of morbidity and mortality. Nearly all human vascular diseases have arterial segment-specific tropisms despite identical exposures to genetic and environmental risk factors. Understanding the cellular and transcriptomic determinants of arterial identities may hold the key to identifying novel pathophysiology and potential therapies. Methods: To specifically determine arterial site-specific differences independent of inter-individual variation, we have generated a human arterial cellular atlas by simultaneously collecting and analyzing up to 8 arterial sites from multiple healthy transplant donors. We performed single cell transcriptomic analysis on arterial segments to determine the differences in cellular composition and transcriptomic programs. We subsequently integrated human genetic data with cell-type specific transcriptomic differences across vascular beds to identify probable causal cells and causal genes associated with human vascular phenotypes. Results/Conclusions: Single cell transcriptomic analysis of &gt;150,000 cells sequenced at &gt;50,000 reads per cell revealed that the dominant cellular drivers of transcriptomic differences between distinct arterial segments, i.e. determinants of arterial identity, are fibroblasts and smooth muscle cells, not endothelial cells or macrophages. Adult vascular cells transcriptomes from different segments are most influenced by their embryonic origins but not by anatomical proximity. Differentially regulated genes in fibroblast across different vascular beds were particularly enriched for vascular disease associated genetic signals, suggesting a prominent role for these cells in human disease. While the majority of endothelial cells were transcriptionally similar across vascular beds, a rare, previously undescribed, cluster of endothelial cells were identified who expressed segment-specific transcriptomic signatures. Differentially expressed genes in these cells were enriched for vascular disease signals, suggesting a possible role of these rare cells in human disease.
Abstract P2054: Epigenetic Regulation Of TLR2 By Gut Microbial Antigens Aggravates Myocardial Fibrosis Through Activating Myd88/IRAK4/NF-kB Signaling In Type 2 Diabetes
Authors: Ram Prasad, Prabhat Ranjan, Jason L Floyd, Angela Harbour, Aayush Rohella, Suresh K Verma, Maria Grant
Journal: Circulation Research (2022)

Background: Type 2 diabetic (T2D) patients are 40% more likely to develop cardiovascular diseases compared to healthy individuals. Previously, we have shown that circulating gut peptides such as peptidoglycan (PGN) aggravate myocardial fibrosis through DNA hypomethylation-induced activation of TLR2; however, the underlying molecular mechanisms responsible remain elusive. Hypothesis: Gut microbial antigens activate MyD88/IRAK4/NF-κB signaling through TLR2 in cardiac tissue, resulting in myocardial fibrosis and cardiac dysfunction in T2D. Methods: Gut barrier integrity, cardiac inflammation, and DNA hypomethylation (5hmC) were measured in cardiac tissue via IHC, qPCR, ELISA, and western blot analysis in db/db mice, a murine model of T2D with 4 months of diabetes and age-matched controls. PGN-treated cardiac fibroblasts were analyzed via in-vitro studies with and without IRAK4 and NF-κB inhibitors. Results: db/db mice exhibited cardiac dysfunction and myocardial fibrosis as measured by reduced LVEF and LVFS with increased LV mass and collagen synthesis. These mice also exhibited higher gut permeability as observed by reduced tight junctional proteins (ZO-1, p120-catenin, and VE-cadherin, YAP, PV1) and increased levels of plasma FABP-2. The levels of PGN were higher in plasma (p&lt;0.003) and cardiac tissue (p&lt;0.001) of db/db mice. The expression of TLR2 (p&lt;0.003) and pro-inflammatory cytokines IL-1β (p&lt;0.008) and TNF-α (p&lt;0.0004) were significantly up-regulated in diabetic hearts compared to WT. Expression of 5hmC was significantly higher (p&lt;0.001) in the hearts of diabetic mice. Increased expression of 5hmC, ten-eleven translocation 1-3 (TET-1, 2, 3), IL-1β, IL-6, and TNF-α were also observed in PGN-treated cardiac fibroblasts. IRAK4 (PF-06650883; 10μM) and NF-κB (CAPE; 50 μM) inhibition reduced the PGN-mediated fibroblast activation, resulting in reduced inflammation. Conclusions: Increased circulating gut microbial antigens by induction of systemic and cardiac inflammatory pathways result in damage to the myocardium of db/db mice. Therapies designed to restore the gut barrier and reduce TLR2 activation may potentially minimize the risk of diabetes-induced cardiovascular complications.
Abstract EC105: A Mouse Model Carrying The R502W Mutation In Cardiac Myosin Binding Protein C (cMyBP-C) Leads To Hypertrophic Myocardial Remodeling In The Absence Of &lt;cMyBP-C&gt; Haploinsufficiency
Authors: Laura Sen-Martín, Ángel Fernández-Trasancos, Miguel Lopez-Unzu, David Sánchez-Ortiz, María Rosaria Pricolo, Jorge Alegre-Cebollada
Journal: Circulation Research (2022)

Background: Familial cardiomyopathies are caused by inherited genetic mutations resulting in anatomical and/or mechanical alterations that compromise cardiac function. The missense variant R502W in cardiac myosin-binding protein C (cMyBP-C) is the most frequent mutation leading to hypertrophy cardiomyopathy (HCM) in humans. Protein and mRNA levels have been proposed not to be altered by this mutation, which points towards pathomechanisms not involving cMyBP-C haploinsufficiency. To test the hypothesis that R502W variant induces HCM remodeling despite preserved cMyBP-C levels, CRISPR/Cas9-based genetic engineering was used to generate a knock-in (KI) mouse model harboring the R502W mutation in murine cMyBP-C. Methods: Histology, echocardiography and magnetic resonance imaging were employed to characterize the cardiac phenotype of KI mice. Protein and cMyBP-C mRNA levels were quantified by Western Blot and qPCR. Immunofuorescence in neonatal cardiomyocytes was used to analyze protein localization. Alteration of myosin conformations was assessed in permeabilized myofibrils using Mant-ATP pulse-chase experiments. Transcriptomic analysis was performed to confirm upregulation of hypertrophic cardiac remodeling programs. Results: We observe higher heart weight to tibia length ratio starting at 18 weeks old homozygous KI mice, which is accompanied by thicker trabeculae, altered ventricle geometry, reduced left ventricular systolic and diastolic function. Fibrosis and hypertrophy at the cardiomyocyte level were detected at 18 weeks of age. Biochemical and immunofluorescence analyses demonstrate that cMyBP-C mRNA, protein levels and localization are not altered by the mutation. Myosin conformations appear largely unaffected in homozygous KI mice. Conclusion: We propose that pathogenicity of the R502W mutation stems from mechanisms that do not involve cMyBP-C haploinsufficiency. We expect that further investigation of R502W mice will shed light on the molecular triggers of HCM caused by cMyBP-C point mutations not triggering protein haploinsufficiency.
Abstract P1008: Bioelectric Sutures Generated From HiPSC-derived Cardiomyocytes Enable <i>In Vitro</i> Electrical Coupling Between Engineered Cardiac Tissues
Authors: Arvin H Soepriatna, Jenny Wei, Elena Song, Bum-Rak Choi, Glenn R Gaudette, Kareen L Coulombe
Journal: Circulation Research (2022)

Heart attack survivors live with permanent damage in their hearts and are at higher risk of developing heart failure. Current treatments do not directly repair or restore function in the damaged tissue. Implanting engineered cardiac tissues (ECTs) to restore contractility to the damaged myocardium is a promising therapy. However, this approach is challenged by poor integration between the implanted ECT and the host heart. To address this issue, we developed a bioelectric suture capable of propagating electrical signals to improve coupling between the two interfaces. We differentiated ventricular cardiomyocytes (CMs) from human induced pluripotent stem cells (hiPSCs) following a well-adopted small molecule modulation of the Wnt signaling pathway. Metabolic-based lactate purification was performed to increase CM purity to &gt; 80%, evaluated by flow cytometry analysis of cardiac troponin-T. We constructed fibrin threads by coextruding fibrinogen and thrombin through a blending tip connector into a HEPES bath. Polymerized, stretched, and dried threads were coated in Matrigel, clamped to suture heads, and seeded with hiPSC-CMs mixed with 5% human ventricular cardiac fibroblasts at a density of 5x10 5 cells/cm for 72 hours. We cultured the conductive and contractile sutures for 2 weeks under 1 Hz electrical stimulation. Optical mapping was performed to characterize electrical properties of bioelectric sutures, including action potential duration (APD) and conduction velocity (CV). Bioelectric sutures were electromechanically active with APD 100 = 547 +/- 29 ms and CV = 25.1 +/- 5.9 mm/s. a-actinin and connexin-43 staining revealed that hiPSC-CMs preferentially aligned with the thread and formed significant gap junctions, suggesting electrical syncytium formation. Preliminary results and ongoing work showed that bioelectric sutures sutured to two separate ECTs electrically coupled within 3 days, enabling directed electrical propagation from one tissue to the other. Collectively, these results demonstrate that bioelectric sutures establish a CM bridge for electrical propagation, which may improve the integration of implanted ECTs with the host heart and enable the development of therapies to treat diseases of cardiac electrical conduction.
Tuberculous pseudo-aneurysm of the descending thoracic aorta
Authors: D Sandron, P Patra, P Lelann, J Bouillard, D Pioche
Journal: European Respiratory Journal (1988)

A tuberculous pseudo-aneurysm of the thoracic descending aorta was found in a 57 year-old female with haemoptysis three months after successful chemotherapy for a miliary tuberculosis. After aortic angiography, the aneurysm was resected and the aorta was repaired with a Dacron prosthetic graft. The patient is doing well one year after the operation.